Mobile wireless communication systems are well known in the art. Within such systems, a plurality of mobile terminals, such as cellular telephones, push-to-talk radios, etc., are able to communicate with one another via wireless channels supported by a wireless infrastructure. Traditionally, such mobile terminals only supported voice communications. Recently, however, the processing power available within such mobile terminals has increased to the point that, in addition to voice transmission services, it is not uncommon for mobile terminals to include, for example, instant messaging applications, electronic mail applications, calendar applications, address book applications, etc. Indeed, some service applications supported by mobile terminals are capable of implementing more than one of these functions. Service applications of this type are typically implemented using stored software programs on a mobile terminal that interact with a corresponding network-based service provider.
This is further illustrated in FIG. 1 in which a plurality of mobile terminals 100 (only one shown for simplicity) communicate with a plurality of service providers 101 via a publicly available network 103 such as the Internet or World Wide Web (WWW) and a wireless network 105. In particular, each of the service applications 107 establishes communications with a corresponding service provider 100 via a unique session 109. In the illustrated example, two instant messaging (IM) applications 107a,b are in communication 109a,b with corresponding IM service providers 101a,b. Similarly, an email application 107c and a synchronization-capable application 107d (e.g., a calendar or address book application) are likewise in communication 109c,d with corresponding email and synchronization service providers 101c,d. 
Typically, each session 109 is implementing using the so-called Transmission Control Protocol (TCP) as known in the art. Quite often, TCP connections are implemented on top of Internet Protocol (IP) addresses (i.e., addresses uniquely associated with individual mobile terminals), as known in the art. Such TCP/IP connections (typically implemented in fixed, wired networks) allow applications running on different hosts to reliably exchange streams of data. However, in a wireless environment such as that depicted in FIG. 1, the usefulness of such TCP/IP connections is diminished given the widely-fluctuating reliability of wireless channels between the wireless network 105 and the mobile terminal 100. In such an environment, it is quite typical for the TCP/IP connections to be dropped, necessitating re-establishment of the connections. Furthermore, it is not uncommon for mobile terminals to be equipped to work with multiple communication system types, e.g., a wide-area system such as General Packet Radio Service (GPRS) and local area systems such as “WI-FI” systems. In such devices, the mobile terminal will switch to the lower-cost system when possible. However, this has the effect of requiring re-assignment of an IP address, thereby terminating any existing TCP connections. Because TCP/IP connections are relatively expensive to establish, the need to frequently re-establish such connections make this approach less attractive.
Additionally, the use of multiple connections 109 is less efficient because each connection 109 propagates the full communication protocol all the way to the mobile terminal 101, including all header information, thereby making implementation at the mobile terminal 101 more complex. Various solutions have been proposed to address the complexity of communications caused by multiple service applications. For example, the so-called Extensible Messaging and Presence Protocol (XMPP) and Instant Messaging and Presence Service (IMPS) have been developed as common protocols for instant messaging. However, in addition to being a relatively inefficient, these protocols are limited to support of instant messaging service and do not provide additional support for email operations, synchronization operations, etc.
It would therefore be advantageous to provide reliable and efficient techniques that allow multiple service applications to communicate with their corresponding service providers such that the limitations of prior art approaches described above may be overcome.